<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>外部的css文件</title>
    <link rel="stylesheet" href="css/b.css">
    <script>
        document.write()
    </script>
</head>
<body>
<div id="div1">传智播客</div>
<div>黑马程序员</div>

</body>
</html>